Dynamic soaring of sailplanes over open fields

Dynamic soaring of a sailplane in the Earth's atmospheric boundary layer was computationally investigated over a range of conditions to explore the feasibility of sustained unpowered flight over open fields by taking advantage of wind shear. A point-mass sailplane model was studied, as well as a full six-degree-of-freedom piloted sailplane model. For the point-mass model, parameter sweeps were performed around a baseline 3-m (9.58-ft) wingspan sailplane having a weight of 15 kg (33 lb) and an aspect ratio of 20. Results from the point-mass model show that, in certain highwind conditions, dynamic-soaring energy-conserving orbits are possible for flight trajectories extending from the ground to ≈200 m (656 ft) aloft. A six-degree-of-freedom piloted flight simulator was used, and it produced similar results that showed dynamic soaring over open fields for large vertical extents (extreme climb). Together, these results support the conclusion that it is possible to perform dynamic soaring in high-wind conditions through the atmospheric boundary layer to high altitudes over open land with model-scale unpowered sailplanes having both high wing loadings and high lift-to-drag ratios.